Conventionally, in digital broadcasting data transmitted from a broadcast station, a conditional access system is often used in which a program (content) to be broadcasted is scrambled and a scrambling key used to descramble the scrambled content is given only to a viewer who signs up for a TV subscription (contract). In the conditional access system, the broadcast station side sends the EMM (Entitlement Management Message) that is an individual information including information of an expiration date for viewing, for example, to each viewer who signs up for the TV subscription. In the viewer side, by obtaining the scrambling key to descramble the scrambled program based on the received EMM, it is possible to view the program scrambled in the conditional access system.
Because the EMM has the expiration date, an EMM including a new expiration date is transmitted to the viewer who continues the TV subscription before the old expiration date is expired. However, if the EMM is not received by the viewer side before the expiration date for any reason such that the viewer did not use a receiver in days while a main power source of the receiver is turned off, for example, the viewer may not be able to view the program which is continued to be subscribed. In such a case, an error message such that a TV subscription has not been subscribed is displayed by the reciever. For example, a rule of 4.18 error notification screen, chapter 4, Required Specifications of Receiver of the ARIB (Association of Radio Industries and Businesses) in TR-B15 Ver. 4.6 (ARIB TECHNICAL REPORT, OPERATIONAL GUIDELINES FOR DIGITAL SATELLITE BROADCASTING) defines as follows.    Example 5: Non-contractual (expired)    The subscription has been expired.    Please contact to the customer center of the channel you are watching.    Code: ****    In this case, a lot of efforts is required for the viewer to ask the broadcast station to retransmit the EMM and for the broadcast station to make as setting for retransmit the EMM, for example. Not only that, but because the viewer sees the error message such as that in the example, it causes the viewer who seeks to continue the TV subscription discomfort.